Stream.CanRead 屬性

  • 參考

定義

命名空間:
System.IO
組件:
System.IO.dll
組件:
System.Runtime.dll
組件:
netstandard.dll
組件:
mscorlib.dll

在衍生類別中覆寫時，取得指示目前的資料流是否支援讀取的數值。

public:
 abstract property bool CanRead { bool get(); };
public abstract bool CanRead { get; }
member this.CanRead : bool
Public MustOverride ReadOnly Property CanRead As Boolean

屬性值

Boolean

如果資料流支援讀取，則為 true；否則為 false。

範例

以下是使用屬性的範例 CanRead 。

using namespace System;
using namespace System::IO;
int main( void )
{
   FileStream^ fs = gcnew FileStream( "MyFile.txt",FileMode::OpenOrCreate,FileAccess::Read );
   if ( fs->CanRead && fs->CanWrite )
   {
      Console::WriteLine( "MyFile.txt can be both written to and read from." );
   }
   else
   {
      Console::WriteLine( "MyFile.txt is not writable" );
   }

   return 0;
}

using System;
using System.IO;

class TestRW
{
    public static void Main(String[] args)
    {
        FileStream fs = new FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read);
        if (fs.CanRead && fs.CanWrite)
        {
            Console.WriteLine("MyFile.txt can be both written to and read from.");
        }
        else if (fs.CanRead)
        {
            Console.WriteLine("MyFile.txt is not writable.");
        }
    }
}

Imports System.IO

Class TestRW

    Public Shared Sub Main()
        Dim fs As New FileStream("MyFile.txt", FileMode.OpenOrCreate, FileAccess.Read)
        If fs.CanRead And fs.CanWrite Then
            Console.WriteLine("MyFile.txt can be both written to and read from.")
        Else
            If fs.CanRead Then
                Console.WriteLine("MyFile.txt is not writable.")
            End If
        End If
    End Sub
End Class

備註

如果衍生自的類別 Stream 不支援讀取，則呼叫 Read 、 ReadByte 和 BeginRead 方法會擲回 NotSupportedException 。

適用於

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